Tarsal tunnel syndrome
Tarsal tunnel syndrome is a compression of the posterior tibial nerve in its osteofibrous tunnel at the ankle and foot. This nerve compression disrupts daily life and sports activities. At The Foot Clinic, we care for patients with plantar fasciitis and tarsal tunnel syndromes.
Definition and understanding of tarsal tunnel syndrome
Tarsal tunnel syndrome is a condition characterized by the compression of the posterior tibial nerve. This nerve, passing through the tarsal tunnel, can be compressed by tissue thickening, trauma, a cyst, a lipoma, or varicose veins. Tarsal tunnel syndrome should be considered in the presence of plantar fasciitis that is resistant to appropriate medical treatment.
Causes and risk factors of tarsal tunnel syndrome
Tarsal tunnel syndrome is a condition resulting from compression of the posterior tibial nerve at the ankle, specifically in the tarsal tunnel. This compression can be caused by various conditions and risk factors.
- Trauma: Direct injuries, such as fractures or severe sprains of the ankle, can lead to inflammation or swelling in the tarsal tunnel region, thus compressing the posterior tibial nerve. Such trauma can also cause anatomical changes, such as bone spurs or cysts that reduce the available space for the nerve.
- Inflammation: Inflammatory conditions, such as tenosynovitis (inflammation of the tendon sheaths) or arthritis, can cause thickening of the tissues surrounding the tarsal canal. This tissue hypertrophy reduces the available space, putting pressure on the posterior tibial nerve. Additionally, systemic diseases like hypothyroidism can cause generalized tissue swelling, contributing to nerve compression.
- Mechanical factors: Biomechanical abnormalities of the foot, such as flat feet (excessive pronation), can alter the natural alignment of the ankle and foot. These deformities increase tension on the tarsal canal, promoting compression of the posterior tibial nerve. Wearing inappropriate footwear, especially shoes that are too tight or ill-fitting, can also put excessive pressure on this area, worsening symptoms.
- Systemic diseases: Certain medical conditions, such as diabetes or rheumatoid arthritis, can damage peripheral nerves or cause inflammation of the ankle joints, thus contributing to the development of tarsal tunnel syndrome. These diseases increase the risk of nerve compression due to the inflammation or structural changes they induce.
- Idiopathic cases: In about 20% of cases, no specific cause is identified. However, predisposing factors such as female gender, diabetes, and rheumatoid arthritis can increase the risk of developing this condition.
It is important to consult a foot and ankle specialist as soon as symptoms suggestive of tarsal tunnel syndrome appear, such as pain, numbness, or tingling in the ankle and foot. Early diagnosis allows for appropriate management, thus limiting the risk of chronic nerve suffering.
Symptoms and clinical manifestations of tarsal tunnel syndrome
Pain is the main symptom of tarsal tunnel syndrome. This pain is usually difficult for patients to describe, as it is neuropathic in origin and does not correspond to the typical pain experienced from everyday or sports-related injuries. It manifests as burning, tingling, numbness, traction sensations, and feelings of compression.
Unlike plantar fasciitis, the pain associated with tarsal tunnel syndrome gradually intensifies throughout the day, becoming particularly bothersome in the evening and potentially causing insomnia. Nocturnal awakening is a common presentation in cases of posterior tibial nerve compression.
The posterior tibial nerve bifurcates at the level of the posterior ankle into three terminal branches: the sensory calcaneal branch, which innervates the heel pad; the medial calcaneoplantar branch, responsible for cutaneous sensation over the plantar arch toward the hallux; and the lateral calcaneoplantar branch, which produces pain throughout the plantar arch with potential radiation toward the fifth digit.
Diagnosis of tunnel syndrome and additional tests
Tarsal tunnel syndrome is a clinical diagnosis confirmed by physical examination, including Tinel's sign over the posterior tibial nerve. Further workup is required to identify the underlying etiology and exclude differential diagnoses:
- A weight-bearing radiographic assessment of the ankles and feet is requested to look for bony elements that may be responsible for the symptoms.
- An MRI of the ankle is systematically requested to search for compressive elements affecting the nerve. A synovial cyst or a lipoma may be involved in the compression. However, in the vast majority of cases, the MRI does not reveal any compressive elements. The main cause of compression is the presence of varicose veins developed at the expense of the veins running through the tarsal tunnel, which gradually fill throughout the day and compress the nerve.
- An electromyogram is requested to rule out nerve injury. The electromyogram does not contribute to the decision to release the nerve surgically, as it only shows posterior tibial nerve involvement in cases of severe injury. It is performed for prognostic purposes, as significant involvement of the posterior tibial nerve is a factor for incomplete recovery after surgical release.
Therapeutic options in tarsal tunnel syndrome
Functional treatment of tarsal tunnel syndrome is offered as a first-line approach. Physical therapy plays an essential role, providing stretching of the posterior muscle chains and specific exercises aimed at relieving compression of the posterior tibial nerve. At the same time, prescribing anti-inflammatory and pain-relieving medications helps to reduce inflammation and pain. The use of plantar orthotics or orthopedic insoles may be suggested to correct foot posture abnormalities, such as flat foot, and reduce pressure on the nerve.
Surgical treatment
If functional treatment fails to relieve symptoms after about three to six months, surgical intervention may be considered. This procedure involves releasing the posterior tibial nerve by opening the tarsal tunnel and all its layers, in order to relieve nerve compression. The decision to opt for surgery depends on the severity of symptoms and the response to non-invasive treatments.
Personalized follow-up is essential throughout the therapeutic process. After surgical intervention, appropriate rehabilitation is crucial to restore foot function and decrease pain. This rehabilitation includes muscle strengthening exercises, stretching, and techniques aimed at improving foot mobility and stability. Close collaboration between the patient, physical therapist, and physician helps optimize outcomes and promote a good recovery.
Tarsal tunnel syndrome at the Foot Clinic
Any recalcitrant plantar aponeurositis should raise the diagnosis of tarsal tunnel syndrome. A precise analysis of the pain and its characteristics makes it possible to suspect the diagnosis. Clinical examination can reveal nerve irritation, reproducing the pain through specific maneuvers. Usually, imaging assessments are of little benefit. An electromyogram should always be performed to look for signs of chronic suffering of the posterior tibial nerve.
Frequently Asked Questions About Tarsal Tunnel Syndrome
It is a compression of the posterior tibial nerve in an osteofibrous canal located at the ankle, causing neuropathic pain that is difficult for patients to describe. It may involve numbness, electric shocks, burning sensations, or pins and needles, for example.
A complete clinical examination, supplemented by X-rays, an electromyogram, and an MRI, helps confirm the diagnosis, detect chronic nerve damage, and look for compressive elements.
Treatment begins with conservative approaches (physical therapy, medications, and orthotics) and, if necessary, progresses to surgical treatment with neurolysis of the posterior tibial nerve.
Key takeaways
Tarsal tunnel syndrome affects the posterior tibial nerve and manifests as persistent pain impacting quality of life. At The Foot Clinic, we prioritize a personalized approach and modern techniques for an accurate diagnosis and optimal treatment. Regain mobility and comfort thanks to our expertise and tailored follow-up.